Psychogenic non-epileptic seizures (PNES; often called 'pseudoseizures') are clinical events that resemble epileptic seizures (ES) but that are not caused by abnormal brain electrical activity or other physiological problems. These neuropsychiatric events are common, accounting for 20-50% of epilepsy monitoring unit (EMU) discharges. PNES were more common than ES in a recent VAMC EMU study. Most veterans with PNES are on chronic antiepileptic drug (AED) therapy, disabled by what are mistakenly thought to be 'medically refractory' seizures. The cumulative disability and cost within the VA system are particularly concerning given that the delay to diagnosis of PNES is 5-fold longer for veterans than for civilians, with a 4- fold excess of chronic AED usage. The correct diagnosis may go unrecognized for years while disability accrues, and appropriate treatment is not provided. VHA cost implications are considerable (~$55 million/year). PNES are symptoms of underlying psychiatric disorders. Effective treatment and earlier diagnosis of PNES will require an understanding of these co-morbid psychiatric diagnoses. Yet there is currently no information regarding co-morbid psychiatric diagnoses in veterans with PNES. These will likely differ from diagnoses recognized in civilians due to (a) differences in the population (age, sex); (b) differences in background (most veterans with PNES cite traumatic brain injury (TBI) as the cause for these seizures); and (c) differences in health care systems. The VA system includes financial compensations that could foster illness behavior in some patients. The proposed multicenter, prospective study will (for the first time) obtain standardized psychiatric evaluation in a carefully evaluated group of veterans meeting research criteria for PNES, and a comparison group of veterans meeting criteria for ES. We will also evaluate the role of TBI in the genesis of PNES, and the potential intermediary role of post-traumatic stress disorder. Follow-up studies will evaluate the influence of co-morbid psychiatric disorders on the medical and social outcome of veterans with PNES. Patients will be recruited from the EMU services at three active VAMC Epilepsy Centers of Excellence. At the time of diagnosis of PNES or ES patients will undergo (a) standardized psychiatric evaluation using the Structured Clinical Interview for DSM IV and other measures, and (b) assessment of the role of TBI in the development of seizures. TBI evaluation will include both patients' subjective assessment of the role of TBI in the development of seizures, and objective evaluation of TBI related epilepsy risk factors through medical record review. The results of this research will provide a detailed understanding of patterns of psychiatric illness underlying the development of PNES in veterans. This will aid in the early recognition of PNES, and the development of treatment strategies for PNES, with the ultimate goal of reducing long-term disability.